This invention relates to oil absorbent skin wipe products. The invention particularly relates to oil absorbent skin wiping products with an oil absorption indication function.
A significant amount of oil continuously oozes out of the skin of the face, particularly the nose, cheek and forehead. To maintain cleanliness, reduce shine and to improve the spreadability of cosmetics and other skin products it is important to remove any excess surface oil or sebum. Soap and water work to some extent but there are always times when one is not able to wash. Dry methods of removing these facial oils include the use of thin oil absorbent wipe materials. Oil absorbing wipes for removing facial oil have been described in the art. These wipes generally must be thin, conformable and non-abrasive, considerations not relevant to industrial oil absorbent materials.
Conventional paper type wipes have been used to remove facial oil. For example, natural or synthetic papers using vegetable fibers, synthetic pulp or kenaf have been used. These oil absorbent papers however are often irritating to the skin due to the hard and stiff nature of the fibers. To improve their smoothness, these papers have been continuously calendered and/or coated with powders such as calcium carbonate and sizing agents. Calendering however is not necessarily permanent and surface fibers can reform into a rough surface unless substantial amounts of binder or sizing agents are used, which decrease oil absorption. Paper wipes are also poor indicators as to their effectiveness, as papers generally do not significantly change appearance when they have absorbed oil or sebum.
Improvements to oil absorbing papers are described in Japanese Kokai No. 4-45591 which teaches adhering porous spherical beads onto the surface of an oil absorbing paper so as to solve the problems caused by calendering or coating of paper with powders such as calcium carbonate powders. These beads also are used to allegedly increase the capacity of the papers to absorb sebum. Japanese Unexamined Patent Publication (Kokai) No. 6-319664 discloses a high-density oil absorbing paper produced by mixing (a) a pulp material containing vegetable fibers, as the main component with (b) an inorganic filler, followed by paper-making to form a paper with a basis weight of 0.7 g/cm2 or more. However, the oil absorbing papers disclosed in these patent publications still have a limited capacity to absorb oil or sebum and little indicating function as there is little change in opacity or color in the paper when oil is absorbed. Difficulty in confirming oil removal means that users of the oil clearing paper can not evaluate if or how much sebum is removed from the users"" face when using the oil absorbing paper such that makeup and the like can be applied with confidence.
An oil absorbing paper for sebum is also disclosed in Japanese Examined Patent Publication (Kokoku) No. 56-8606, or U.S. Pat. No. 4,643,939, which describes a cosmetic oil absorbing paper produced by mixing hemp fibers with 10 to 70% by weight of polyolefin resin fibers and making a paper with a basis weight of from 12 to 50 g/cm2. This paper will allegedly clear upon absorption of oil but still requires conventional papermaking techniques and would be rough to the touch. Japanese Unexamined Utility Model Publication (Kokai) No. 5-18392, discloses an oil absorbing synthetic paper comprising an oil absorbing paper with a smooth surface coating of inorganic or organic powder material such as clay particles, silica fine-particles, and powdered fibers. These oil-absorbing papers allegedly have some oil indicating effect by clarifying the paper upon oil absorption thus confirming oil absorption. However, the powder coating lowers the oil absorption capacity for these papers and it is still difficult to attain a clear change in the appearance of this type of oil clearing paper after oil absorption.
Japanese Unexamined Patent Publication (Kokai) No. 9-335451 (WO99/29220) discloses an oil wipe made of a porous thermoplastic film. This oil absorbing wipe film has higher oil absorption capacity than the oil absorbing papers and is also superior in confirming removal of oil following wiping as compared to oil absorbing papers. It is believed that the reason for this good oil removal indicating functionality is that these porous thermoplastic films exhibit low light transmittance before oil absorption because of irregular reflection of light, but the light transmittance increases substantially after the micro-pores of the film are filled with oils producing a large change in the film""s opacity or light transmittance, and therefore appearance. This change in opacity clearly confirms to the user the removal of oil or sebum from his or her skin. Further, unlike the paper products, these film based wipes are soft, comfortable, smooth and nonirritating to the skin.
It is an object of the invention provide an oil absorbing wipe having a rapid oil absorption indicating function, such as described in WO99/29220, which product is easy to manufacture.
The invention is directed to oil absorbing wipe materials suitable for wiping a users"" skin or hair and a method for their manufacture. The wipes comprise at least an oil absorbing porous film-like substrate of a thermoplastic material. Generally, the wipe changes transparency or color (a change in L* of about 10 or more) when loaded with oil to provide an oil absorption indication functionality. The wipe is formed by (a) providing a porous film-like substrate of a thermoplastic material capable of absorbing facial or body oils and changing transparency or color, and (b) coating the porous substrate with oil, either continuously or in regions, wherein the oil coating is not sufficient to change the transparency or color of the substrate such that it loses its oil absorption indication functionality. This oil coating being of a nature such that the coated porous substrate has an increased oil absorption indicating functionality.